1. Technical Field
The present invention relates to a nozzle plate, a method for manufacturing a nozzle plate, a droplet discharge head, and a droplet discharge device.
2. Related Art
A droplet discharge device such as an ink-jet printer is commonly provided with a droplet discharge head for discharging droplets. Such a droplet discharge head is known that is provided with a nozzle plate having nozzles (nozzle holes) for discharging an ink as droplets; an ink chamber (cavity) storing the ink therein; and a piezoelectric element deforming a wall of the ink chamber so as to discharge droplets of the ink from the nozzles.
If an ink is attached to a surface of the nozzle plate (a surface positioned at a side from which the ink is discharged) in such the droplet discharge head, an ink which is discharged afterward is influenced by a surface tension, a viscosity, or the like of the ink that has been attached on the surface of the nozzle plate and discharge failure (a phenomenon in which a discharge path of the ink is curved) of the ink occurs. As a result, the ink can not be stably discharged on predetermined positions, thus degrading printing quality. Therefore, a liquid-repellent treatment for preventing attachment of an ink is commonly performed on a surface of a nozzle plate, as disclosed in JP-A-7-228822, as a first example.
Here, such the droplet discharge head is assembled by bonding the nozzle plate and a substrate for forming an ink chamber by a photosensitive adhesive or an elastic adhesive, as disclosed in JP-A-5-155017 as a second example.
However, it is very difficult to precisely control a supply amount of the adhesive in supplying the adhesive between the nozzle plate and the substrate. Therefore, uniform amount of the adhesive can not be supplied, making a distance between the nozzle plate and the substrate uneven. Accordingly, uniform bulks can not be achieved among a plurality of ink chambers formed in a droplet discharge head, or uniform bulks of ink chambers can not be achieved among droplet discharge heads. Further, a distance of the droplet discharge head and a printing medium such as a printing sheet becomes uneven. Furthermore, the adhesive may disadvantageously run out of the bonding part. These problems degrade dimensional accuracy of the droplet discharge head. As a result, even though the discharge failure of the ink droplets is suppressed by the liquid-repellent treatment performed on the surface of the nozzle plate, the printing quality of the ink-jet printer can not be sufficiently improved.